Intake air control device for internal combustion engine of fuel injection type

ABSTRACT

An intake air control device adapted for use in an internal combustion engine of fuel injection type. One embodiment comprises a butterfly type control valve provided in an intake air passage upstream or downstream of a throttle valve mounted therein. The control valve includes a flap member rotatable about a shaft secured thereto slightly off the center of the air passage. Thus, upon actuation of an acceleration control member, the control valve is opened by the flow of intake air after a predetermined time lapse from the moment the acceleration control member is actuated, thereby gradually increasing the amount of the intake air. Another embodiment employs a Venturi type piston valve to serve the same purposes.

United States Patent [1 1 Nambu et al.

[451 Apr. 3, 1973 a 22 Filed:

[54] INTAKE AIR CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE OF FUEL INJECTION TYPE [75] Inventors: Shyuya Nambu, Yokohama; Shigeo Aono, Yokosuka, both of Japan [73] Assignee: Nissan Motor Company, Limited, Kanagawa-ku, Yok0hafma,.lapaii 211 Appl. No.: 77,535

[30] Foreign Application Priority Data 2,914,051 11/1959 Dolza et a1 ..123/119 R FOREIGN PATENTS OR APPLICATIONS 495,538 1/1954 Italy ..t ..123/103 D 660,311 11/1951 Great Britain ..261/44 R 962,829 7/1964 Great Britain ..123/139 AW Primary Examiner-Tim R. Miles Attorney-John Lezdey [57] ABSTRACT An intake air control device adapted for use in an internal combustion engine of fuel injection type. One embodiment comprises a butterfly type control valve provided in an intake air passage upstream or downstream of a throttle valve mountedtherein. The control valve includes a flap member rotatable about a shaft secured thereto slightly off the center of the air passage. Thus, upon actuation of an acceleration control member, the control valve is opened by the flow of intake air after a predetermined time lapse from the moment the acceleration control member is actuated, thereby gradually increasing the amount of the intake air. Another embodiment employs a Venturi type piston valve to serve the same purposes.

1 Claim, 6 Drawing Figures ['MENIEDAPM 1915 3,724,822

sum 1 [IF 3 INVENTOR sum YA M/geu +$mo Anya ATT NE PATENTEDAPM 1975 3,724,822

SHEET 3 [1F 3 INVENTOR BY Q! E ATTO E INTAKE AIR CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE OE FUEL INJECTION TYPE This invention relates generally to a fuel injection system for an internal combustion engine of a motor vehicle and more particularly to devices adapted for use in such a system and capable of controlling the flow rate of intake air to be supplied to the individual combustion chambers of the engine during acceleration.

In a fuel injection system for an internal combustion engine, mixing of fuel with air is made by injecting the fuel into the air existing in the combustion chambers or into the air in the intake manifold relatively close to the respective chambers. Therefore, the problem of uneven distribution of the fuel is encountered due to the geometry of the intake manifold. It is, therefore, a usual practice to provide, in the internal combustion engine of fuel injection type, a throttle valve and an intake manifold designed for high output performance. The throttle valve thus designed is usually located in an intake air passage leading tothe intake manifold and includes a flap member having a relatively large diameter. However, when such a flap member is suddenly tilted to its open position, the amount of intake air increases so abruptly that the amount of the fuel can not increase proportionally to the increase in the amount of air, resulting in the failure to effect smooth acceleration of a vehicle. Or otherwise, if the increase in the amount of fuel can follow the increase in the amount of air, the shaft torque rises too sharply, causing the persons on the vehicle to feel a shock.

It is, therefore, an object of this invention to provide an improved intake air control device adapted for use in an internal combustion engine of fuel injection type with a view to overcoming the above-stated disadvantages. I

It is another object of this invention to provide an improved intake air control device, as above, which operates to gradually increase the amount of intake air in response to actuation of an acceleration member for acceleration purposes of a vehicle.

It is a further object of this invention to provide an improved intake air control device, as above, having a butterfly valve of the same type as a throttle valve.

It is yet a further object of this invention to provide an improved intake air control device, as above, having a Venturi type piston valve.

In the drawings:

FIG. 1 is a schematic view, partially in section, of a fuel injection system having incorporated therein an intake air control device according to one embodiment of this invention;

FIGS. 2(a) and (b) are front and side views of the butterfly type intake air control device shown in FIG. 1;

FIG. 3 is a graph showing a time relationship between throttle position, amount of intake air and shaft torque;

FIG. 4 is a side view of an intake air control device constructed in accordance with another embodiment of this invention; and

FIG. 5 is a side section of a piston type intake air control device according to a further embodiment of this invention.

Referring now to FIG. 1, there is shown a fuel injection system having incorporated therein an intake air control device of this invention. The fuel injection system as shown is of speed-density-metering type in which the amount of intake air is controlled by a throttle valve 10, while the amount of fuel to be mixed with the intake air is controlled by a metering device 11 pneumatically connected to an intake manifold 12 by way of a conduit 13. The metering device 11 is mounted on an injection pump 14 which is adapted to be driven by an engine (not shown) to deliver fuel under pressure to injection nozzles 15 provided in the intake passage of the individual combustion chambers 16 of the engine.

The intake air is admitted through an air cleaner 17 into an intake air passage 18 having the throttle valve 10 mounted therein. The throttle valve 10 is operatively associated with an acceleration control member or an accelerator pedal 19 through a mechanical linkage,

as generally indicated at 20, so as to allow a predetermined amount of air to flow through the air passage 18 in response to the movement of the accelerator pedal 19. The intake air leaving the air passage 18 is fed to the individual combustion chambers 16 of the engine by way of the intake manifold 12.

Mounted in the intake air passage 18 upstream of the throttle valve 10 is the intake air control device of this invention which may comprise a butterfly valve 21 of the same type as the throttle valve 10. This butterfly valve 21 is also adapted to be tilted in the intake air passage 18 to allow a predetermined amount of air to flow therethrough. While the butterfly valve 21 is shown as located in the air passage 18 upstream of the throttle valve 1 0, it is to be understood that the butterfly valve 21 could equally as well be located downstream of the throttle valve 10.

Reference should now be made to FIGS. 2(a) and (b) wherein the intake air control device according to one embodiment of this invention is shown in more detail. The butterfly valve 21 comprises a flap member 22 adapted to be tilted in the air passage 18, a shaft 23 secured to the flap member 22 for rotating therewith, an arm member 24 secured to one end of the shaft 23 so as to extend substantially perpendicularly thereto and a weight member 25 secured to the free end of the arm member 24. As shown, the shaft 23 is pivotally mounted on the wall slightly off the center of the air passage 18, so that when the intake air is caused to pass through the air passage 18 in the direction of arrow 26 the flap member 22 is tilted in a clockwise direction as viewed in FIG. 2(b) to a position at which an equilibrium exists between the moment of rotation developed by the intake air and that developed by the weight 25. Thus, the tilting position effects a gradual increase in the amount of air flow passing through the effective area defined by the circumferential edge of the flap member 22 and the inner wall of the air passage 18. It is to be noted that since a combination of the arm member 24 and the weight 25 has a certain amount of inertial mass the butterfly valve 21 begins to open after a predetermined time lapse from the moment the throttle valve 10 begins to open in dependence on the actuation of the acceleration control member 19. The period of time depends upon the inertial mass provided by the arm member 24 and the weight member 25.

FIG. 3 graphically shows a time relationship between throttle position, amount of intake air and shaft torque.

As the throttle valve is opened as shown by a solid line 27, the amount of intake air increases abruptly as shown by a solid line 28 and the shaft torque may also increase abruptly as shown by a solid line 29. Such an abrupt change inthe shaft torque would often tend to make the persons in a car feel a shock. Or otherwise, some difficulties are experienced in effecting accelereration since the increase in the fuel delivered cannot follow the increase in the amount of intake air so that the mixture is relatively lean, with the resultant momentary decrease in the shaft torque as indicated by a phantom line 30.

However, with the present intake air control device 21 mounted in the air passage 18, the above-stated disadvantages can be overcome. That is, upon opening of the throttle valve 10, the butterfly valve 21 commences to open after the lapse of a certain period of time due to the inertia inherent to the arm member 24 and the weight member 25. Thus, the amount of intake air in creases more gradually as shown by a broken line 31. As a result, the shaft torque is increased in proportion to the less abrupt increase in the amount of intake air, as indicated by a broken line 32.

It is to be noted here that the manner in which the amount of intake air and the shaft torque increases can be modified by varying the length of the arm member 24 and the weight of the weight member 25. However, in the case where the arm member 24 is too long and the weightmember 25 is too heavy, the butterfly valve 21 tends not to be fully opened even when the throttle valve 10 is fully opened. When this occurs, the butterfly valve 21 provides for resistance to air intake, causing a reduction in the output torque.

FIG. 4 illustrates a modification of the intake air control device shown inFIGS. 1 and 2, in which the abovesaid problem concerning the resistance to air intake is eliminated. As shown, this modification includes a linkage for controlling the opening of the flap member 22, which linkage is operatively connected to the flap member 22 and throttle valve 10 for tilting the flap member 22 to its fully open position in dependence on the full opening of the throttle valve 10. The arm members 24 and'33 are secured to the respective shafts 23 and 34 for the butterfly valve 21 and the throttle valve 10 and provided with bell crank portions 35 and 36 extending downwards in substantially parallel relationship to each other when the valves are closed. Each of the bell crank portions 35 and 36 has pins 37 and 38, respectively, secured to one end thereof.

Mounted on the pin 38 for rotating thereabout is arod member 39 having an elongated slot 40 longitudinally formed near one end portion thereof to movably receive the pin 37 provided at the end portion of the bell crank 35. With such an arrangement, the butterfly valve 21 is forcedly moved to its fully open position by the action of the rod member 39 when the throttle valve 10 is fully opened.

FIG. 5 illustrates a further embodiment of the present intake air control device. As shown, there is provided on the outer wall 40 of the air passage 18 a cylindrical housing 41 having a hollow piston 42 reciprocally accommodated therein. The wall 40 of the air passage 18 is formed with an opening 43 through which the piston 42 extends into the air passage 18. The piston 42 is biased through the opening 43 toward the inner flat wall or bottom 44 of the air passage 18 by the action of a spring member 45 accommodated between the end wall 46 of the cylindrical housing 41 and the end of the piston 42 projecting into the air passage 18. The piston 42 is hollow and is formed at its end projecting into the air passage 18 with a small opening 47. The cylindrical housing 41 is formed in its side wall near the air passage 18 with a vent hole 48 which introduces atmospheric pressure into a space 49 defined by the cylindrical housing 41, piston 42 and outer wall 40 of the air passage 18. The opening 47 is adapted to communicate the air passage 18 with a space 50 defined by the piston 42 and cylindrical housing 41.

Between the end of the piston 42 projecting into the air passage 18 and the bottom 44 of the air passage 18 there is provided a Venturi of a constricted section (not numbered) through which the intake air flows. As the air flows through the constricted section, a partial vacuum is produced at the Venturi. Since the piston 42 has the small opening 47 formed at the extending end thereof, the partial vacuum develops within the space 50. Thus, the piston 42 is moved toward the end wall 46 against the action of the spring member 45 by the pressure difference between the two spaces 49 and 50. The effective area of the Venturi is controlled by the displacement of the piston 42 depending upon the amount of the intake air passing therethrough. It is to be noted that in this embodiment, also, the piston 42 begins to permit a flow of the intake air through the air passage 18 after a predetermined time lapse controlled by the inertial mass provided by the piston 42.

What is claimed is:

1. An air intake control device for an internal combustion engine of fuel injection type of a motor vehicle having an air intake passage communicating with individual combustion chambers of the engine and a throttle valve disposed in said air intake passage,.said air intake control device comprising a control means adapted to be provided in said air intake passage for effecting a gradual increase in the amount of air flow passing therethrough after a predetermined time lapse from the moment an acceleration control member is actuated to open said throttle valve for acceleration of the motor vehicle, said control means including a flap member adapted to be tilted in said air intake passage for allowing a gradually increasing amount of airto flow through the effective area defined by the circumferential edge thereof and the inner wall of said air intake passage, a shaft member pivotally mounted on the wall slightly off the center of said air intake passage, an arm member secured to one end of said shaft member and extending substantially perpendicularly to said shaft member, a weight member secured to one end of said arm member for controlling the period of said time lapse by the inertial mass thereof together with said arm member, and an opening control means operatively connectedv to said flap member and said throttle valve for, tilting said flap member to its fully open position in dependence on the fully opening of said throttle valve, said opening control means including a first bell crank secured to the shaft of said throttle valve for rotating therewith and having a first pin at one end thereof, a second bell crank secured to said shaft member for rotating therewith and having a second pin at one end thereof, and a rod member mounted on said first pin for rotating thereabout having an elongated slot longitudinally formed near one end thereof for movably receiving said second pin. 

1. An air intake control device for an internal combustion engine of fuel injection type of a motor vehicle having an air intake passage communicating with individual combustion chambers of the engine and a throttle valve disposed in said air intake passage, said air intake control device comprising a control means adapted to be provided in said air intake passage for effecting a gradual increase in the amount of air flow passing therethrough after a predetermined time lapse from the moment an acceleration control member is actuated to open said throttle valve for acceleration of the motor vehicle, said control means including a flap member adapted to be tilted in said air intake passage for allowing a gradually increasing amount of air to flow through the effective area defined by the circumferential edge thereof and the inner wall of said air intake passage, a shaft member pivotally mounted on the wall slightly off the center of said air intake passage, an arm member secured to one end of said shaft member and extending substantially perpendicularly to said shaft member, a weight member secured to one end of said arm member for controlling the period of said time lapse by the inertial mass thereof together with said arm member, and an opening control means operatively connected to said flap member and said throttle valve for tilting said flap member to its fully open position in dependence on the fully opening of said throttle valve, said opening control means including a first bell crank secured to the shaft of said throttle valve for rotating therewith and having a first pin at one end thereof, a second bell crank secured to said shaft member for rotating therewith and having a second pin at one end thereof, and a rod member mounted on said first pin for rotating thereabout having an elongated slot longitudinally formed near one end thereof for movably receiving said second pin. 